1. Field of the Invention
The present invention relates to a cell for gas generation, particularly for the operation of a lubricant dispenser, having two electrodes to be connected to a circuit containing a power source, and an aqueous electrolyte fluid located between the two electrodes, containing an azide having the formula XN3, for electrochemical generation of a gas containing nitrogen (N2).
2. The Prior Art
In practice, it is known to meter the amount of lubricant that is dispensed by a lubricant dispenser by means of a gas-generating cell, whereby the pressure produced using the gas causes a corresponding exit of lubricant from the dispenser. In this connection, the generation of hydrogen or oxygen at the electrodes of a galvanic cell is known, for example from DE 35 32 335 C2. The cell can itself supply a sufficiently great voltage, if necessary with a zinc anode for generating hydrogen, or with a manganese dioxide cathode for generating oxygen. In this way, the electrolyte stream that flows between the electrodes can be regulated by way of an externally adjustable resistor. In addition, a battery can also be provided, which makes better regulation of the current intensity possible.
A gas cell is known from the reference DE 692 26 770 T2, wherein nitrogen is formed from a sodium azide solution, by means of electrolysis. In the electrolysis of an aqueous sodium azide solution, the gas generation rate quickly drops with the increasing formation of nitrogen. This gas generation rate drop arises because the hydroxide ions that are formed during the reaction result in a great increase in the pH of the solution, as the following reaction equation shows:2NaN3+2H2O→3N2+H2+2 NaOH
At high pH values, the formation of free nitrogen does not take place, and only water is decomposed. Usual buffer substances, e.g. phosphates, are unsuitable for solving this problem, since their buffering capacity is too low.
An improvement is possible, by means of adding potassium iodide and potassium thiocyanate, but these are substances that behave aggressively with regard to metals, so that accordingly, precious metals or graphite electrodes must be used.